drm/i915/dsi: filter invalid backlight and CABC ports

Avoid using ports that aren't initialized in case the VBT backlight or
CABC ports have invalid values. This fixes a NULL pointer dereference of
intel_dsi->dsi_hosts[port] in such cases.

Cc: stable@vger.kernel.org
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/b0f4f087866257d280eb97d6bcfcefd109cc5fa2.1660664162.git.jani.nikula@intel.com

drivers/gpu/drm/i915/display/icl_dsi.c

@@ -2071,7 +2071,14 @@ void icl_dsi_init(struct drm_i915_private *dev_priv)
 	else
 		intel_dsi->ports = BIT(port);
 
+	if (drm_WARN_ON(&dev_priv->drm, intel_connector->panel.vbt.dsi.bl_ports & ~intel_dsi->ports))
+		intel_connector->panel.vbt.dsi.bl_ports &= intel_dsi->ports;
+
 	intel_dsi->dcs_backlight_ports = intel_connector->panel.vbt.dsi.bl_ports;
+
+	if (drm_WARN_ON(&dev_priv->drm, intel_connector->panel.vbt.dsi.cabc_ports & ~intel_dsi->ports))
+		intel_connector->panel.vbt.dsi.cabc_ports &= intel_dsi->ports;
+
 	intel_dsi->dcs_cabc_ports = intel_connector->panel.vbt.dsi.cabc_ports;
 
 	for_each_dsi_port(port, intel_dsi->ports) {

drivers/gpu/drm/i915/display/vlv_dsi.c

@@ -1933,7 +1933,14 @@ void vlv_dsi_init(struct drm_i915_private *dev_priv)
 	else
 		intel_dsi->ports = BIT(port);
 
+	if (drm_WARN_ON(&dev_priv->drm, intel_connector->panel.vbt.dsi.bl_ports & ~intel_dsi->ports))
+		intel_connector->panel.vbt.dsi.bl_ports &= intel_dsi->ports;
+
 	intel_dsi->dcs_backlight_ports = intel_connector->panel.vbt.dsi.bl_ports;
+
+	if (drm_WARN_ON(&dev_priv->drm, intel_connector->panel.vbt.dsi.cabc_ports & ~intel_dsi->ports))
+		intel_connector->panel.vbt.dsi.cabc_ports &= intel_dsi->ports;
+
 	intel_dsi->dcs_cabc_ports = intel_connector->panel.vbt.dsi.cabc_ports;
 
 	/* Create a DSI host (and a device) for each port. */